Dry pipe valve



Oct. 8, 1935. v W K HODGMAN, JR 2,016,547

DRY PIPE VALVE Filed Aug. 25, 1934 VVills K. Hodgman dr.

bym Mae/M Ays.

Patented Oct. 8, 1935 UNITED STATES PATENT OFFICE This invention relates to a dry pipe valve designed for supplying a system such as a nre prevention sprinkler system.

The object of the invention is to provide a conv struction which will prevent water columning taking place and thus the danger f the system becoming inoperative.

This and other objects and features of the invention will appear more fully from the accompanying description and drawing and will be particularly pointed out in the claims.

The drawing illustrates a dry pipe valve ernbodying a preferred form of the invention in which:

Fig. 1 is a vertical cross section taken on the line I-I of Fig. 2, and

Fig. 2 is a generally horizontal cross section taken on the line 2--2 of Fig. l.

As the generalV construction, purpose and use of a dry pipe valve is well known and familiar, it is only necessary to describe in detail those features with which the present invention is particularly concerned.

The present invention is designed particularly for embodiment in a dry pipe valve such as would be used in controlling the supply of water `to. the sprinkler heads in a fire prevention sprinkler system.

As illustrated, the construction comprises the usual cast metal casing having the body portion I and the removable cover portion 2. At the bottom the casing is secured to the water system and the water passage 3 enters vertically at the bottom and terminates with the water valve seat or port 1I. At the top the casing is secured to the sprinkler system and the air pressure in the casing and in the sprinkler system is equalized through the passage 5.

The'casing concentrically of the water valve seat or port 4 for the water passage is provided with an upwardly extending projection 6 terminating in an air valve seat or port 1. Suitable clapper means including a water valve to cooperate with the water port and a peripherally flexible air valve to cooperate with the air port are mounted in the casing to provide for the required movement of the two valves between closed and open position. Such clapper means may be of various construction within the scope of the invention. As a simple and preferred form there is illustrated a swinging clapper pivotally mounted and carrying both the water valve to cooperate with the water port l and the air valve to cooperate with the air port I.

The chamber 8 in the casing which is closed at the bottom by the air valve seating upon the air port 1 constitutes the air pressure chamber in which, under normal conditions, is maintained the necessary air pressure in the sprinkler system. An annular chamber 9 is formed between the water port and the air port when the valves are closed and this chamber is normally open to the atmosphere through the radial opening I0 to which is connected the usual check valve controlled drip which of itself forms no part of the 5 present invention.

The clapper illustrated for closing the water port and the air port comprises a bifurcated arm II having an extended bearing I2 on a shaft I3 mounted horizontally in the casing. In the free end of this arm is vertically and pivotally mounted the stem It of the clapper I5. This clapper is of metal and in the form shown is iinished to provide a central water valve I6 to seat upon the water port 4 and concentric thereof the peripherally flexible air valve I1 to seat upon the air port 'I. The air valve is preferably formed as a flat annulus of rubber and is clamped to the body of the clapper l5 by means of the clamping ring I 8 and the screws I3 which pass through the 20-V clamping ring into the body of the clapper. It will thus be seen that this construction presents a swinging clapper having the central water valve I6 to seat and close upon the water port 4 and the peripherally flexible air valve I1 to seat upon and 25 close upon the air port 1.

Under normal conditions the sprinkler system, and consequently the air chamber 8 in the casing of the dry pipe valve, is iilled with air under pressure and this pressure exerted upon the rela- 30 tively large area of the clapper opposite the air port is sufficient to hold the clapper with the valves seated against the pressure of the water upon the relatively smaller area of the clapper opposite the water port.

In the case of a dry pipe sprinkler system, when a nre occurs and one or more sprinkler heads are opened, the pressure in the air chamber 8 is rapidly reduced well below that suflicient to hold the clapper means closed and consequently the 4o clapper means is moved open and the Water enters the system.

In order to prevent the clapper means from returning to vclosed position, various constructions may be employed. For this purpose in the 45 form of clapper means illustrated the clapper I5 is shown provided near its periphery at one side with a recess filled with lead 20 and the clamping ring I8 is provided with a depending projection 2 I. I n normal position the projection 50 2l is at one side of a rib 22 on the casing. When the clapper I5 has been swung open by the inrush of water through the dry pipe valve, the weight 2!) causes the clapper to rotate at its stem I4 in the arm II and the proportions are such 55 that when this takes place, the projection 2| is brought into such position that i1 the clapper should drop, the projection would rest on top of the rib 22 and thus prevent the clapper from moving to closed position.

But, when for any reason there has been a gradual reduction in the air pressure in the system and consequently in the air chamber 8, a point may be reached where the clapper means is very evenly balanced between the air and water pressures and practically oats on the water so that slight amounts of water ow or surge past the water and air valves into the air chamber. This condition may continue sufiiciently to cause water columning, that is, enough water may work past the valves gradually to form a suiiicient head on top of the air valve to hold both valves closed against the water pressure and thus render it possible for the entire device to be inoperative.

The object of the invention is to prevent any such water columning taking place as the result of a continuing ilow or surge of water into the air chamber.

For this purpose in the preferred construction illustrated a latch member 23 is pivoted at 24 on a projection 25 extending inwardly from the cover 2 of the casing and is provided with a stop 2G limiting its downward movement. This latch cooperates with a shoulder 2l formed on one of the bifurcations of the arm ll of the clapper l5. The latch and projection 2'? are so positioned that if the clapper is opened slightly, the latch will drop over the shoulder 21 and lock the clapper against closing. But it will be remembered that the air valve i l is a flexible member and is made flexible in order to ensure both air and water valves seating firmly under normal conditions. Consequently the latching construction, such as the latch 23 and cooperating shoulder 2l, must be so positioned as to lock the clapper suiciently wide open so that the flexible air valve Il' cannot be forced or bent down on to the air valve seat ll. But in order to swing the clapper to such a position where it is latched or locked with the exible air valve out of reach of its seat, a greater force is required than that resulting from the small hows or surges which are the cause of the difficulty to be overcome.

The present invention provides means for resisting a surge of water past the clapper means by a direct path into the air chamber and thus augmenting the movement of the clapper means suiiiciently to ensure the locking of the clapper means by the latch or locking means. In the construction of pivoted clapper carrying both valves as illustrated this is secured by forming or providing on the clamping ring I8 a baliie ange 28 depending from the clapper interiorly concentric with and quite closely adjacent the air port l. This baiiie flange, as shown in Fig. 2, extends well around the portion of the clapper opposite its pivot and there is thus formed a narrow, vertical, annular passage 29 between the air port l and the projection 28. Consequently any slight flow or surge of water past the water valve i6 and the water port 4, which tends to move in a direct path from the top of the water port to the top oi the air port is instead at iirst deflected downward in the chamber 9 around the bottom edge oi the projection 28 and up between this projection and the air port through the space 29. This resistance to the normal or direct path of iow causes the clapper to rise until the path of flow approaches the normal direct path and thus when the pressure is suiiicient to force the clapper open, the swing of the clapper is augmented sufliciently to ensure the engagement of the latch 23 with the shoulder 2l.

The invention thus ensures that any flow or surge of water past the air valve into the ai1 chamber sufiicient to start water columning is also suiciently augmented in force by the means of this invention to move the clapper means into such position that it is locked with the periphery exible air valve in such a position that it cannot be forced into engagement with and close the air port.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

1. A dry pipe valve comprising a casing, an air pressure chamber in the casing, a water passage having a port opening into the air chamber, an air port in the casing surrounding the water port, a chamber in the casing between the air and water ports normally open to the atmosphere, movable clapper means having a water valve to seat upon and close the water port and a peripherally exible air valve to seat upon and close the air port, means cooperating with the clapper means when moved open slightly by a surge 'of water to lock the clapper means in a position such that the ilegible periphery 0I the air valve cannot be forced into engagement with and close the air port, and means on the clapper means acting to resist a surge of water by a direct path into the air chamber and thus augment the movement of the clapper means by said surge suiiiciently to ensure the said locking of the clapper means by the locking means. Y

2. A dry pipe valve comprising a casing, an air pressure chamber in the casing, a water passage having a port opening into the Vair chamber, an air port in the casing surrounding the water port, a chamber in the casing between the air and water ports normally open to the atmosphere, movable clapper means having a water valve to seat upon and close the water port and a peripherally exible air valve to seat upon and close the air port, means cooperating with the clapper means when moved open slightly by a surge of water to lock the clapper means in a position such that the Yiexible periphery or' the air valve cannot be forced into engagement with and close the air port, and means on the clapper means acting to deect from a direct path between the water and air ports a surge of water into the air chamber and thus augment the movement of the clapper by said .surge sufliciently to ensure the said locking of the clapper means by the locking means.

3. A dry pipe valve comprising .a casing, an air pressure chamber in the casing, a water passage having a port opening into the air chamber, an air port in the casing surrounding the Water nort, a chamber in the casing between the air and water ports normally open to the atmosphere, a swinging clapper having a central water valve to seat upon and close the water port and a peripherally exible air valve to seat upon and close the air port, a latch acting to vengage the clapper when `swung open slightly by a surge of water and lock it in a position such that the exible periphery of the air valve cannot be forced into engagement with and close the air port, and a baie lange depending from the clapper interiorly concentric with and adjacent the air po-rt acting to resist a surge of water by a direct path into the air chamber and thus augment the swing of the clapper by said surge suficiently to ensure its engagement with the latch.

WILLIS K. HODGMAN, JR. 

